LT3950EMSE - 60V 1.5A LED Driver w/ Exponential Dim | ADI
부품 번호: LT3950EMSE ✓ 활성| 수량 | 단가 | 합계 |
|---|---|---|
| 1 | $4.9103 | $4.91 |
| 1,000 | $2.92 | $2,920.00 |
LT3950EMSE 개요
A DC/DC LED driver is a switch-mode power supply specifically engineered to regulate current through a string of high-brightness LEDs rather than regulate output voltage. Within the broader power management IC hierarchy, the LT3950EMSE sits between general-purpose DC-DC converters (LM2591, LMR33640) and lighting-specific drivers (LM3405, LP5024). By combining the inductor-based switching converter and a constant-current regulation loop in one IC, the part eliminates the discrete sense resistor, op-amp, and MOSFET network that a discrete solution would otherwise require, simplifying BOMs in solid-state lighting designs.
Key features include a wide 3 V to 60 V input range, 1.5 A internal switch rating, 200 mV current sense voltage (reducing conduction loss), open-drain fault indicator, programmable soft-start, and an auxiliary PWM input pin for synchronizing the LED brightness to an external MCU. The 2 MHz switching frequency stays above the AM band, while the internal exponential dimming generator removes the need for firmware-based gamma correction. Quiescent current is typically under 1 mA in shutdown.
The LT3950EMSE uses a constant-frequency peak-current-mode control architecture. The internal high-side DMOS switch and current sense amplifier form the inner current loop, while an external resistor on the SENSE pin programs the LED current setpoint. The exposed pad (EP) of the MSOP-16 provides a low-thermal-resistance path (θJA ≈ 38 °C/W on a 4-layer JEDEC JESD51-7 board) so 1.5 A operation is feasible without an external heatsink for moderate VIN-VOUT differentials.
Typical applications include automotive daytime running lights, architectural and signage lighting, MR16 and AR111 LED retrofit lamps, constant-current LED strings, and backlight drivers for industrial displays. Its 60 V rating also makes it suitable for 36 V industrial bus rails or 48 V telecom supply chains.
When designing with this part, pay attention to inductor saturation current (must exceed 2 A), input bulk capacitance for hot-plug events, and PCB thermal copper under the exposed pad. A common pitfall is leaving the exposed pad unsoldered, which can raise junction temperature by 20-30 °C and trigger thermal shutdown at 1.5 A.
This page synthesizes distributor pricing, drop-in alternatives, application notes, and design guidance not consolidated in any single vendor listing, helping engineers select and source the LT3950EMSE faster.
드롭인 대체품: LT3950EMSE — 동일 패키지, 핀 호환. PCB 재작업이 필요한 다른 패키지 부품은 제외됩니다.
이 시리즈의 변형
다음과 드롭인 호환되는 동일 시리즈 모델: LT3950EMSE (동일 폼 팩터 및 풋프린트) — 차이점: Input Voltage Range, MSL Level, Package, RoHS Status, Switching Frequency.
빠른 비교 도구 — 나란히 비교할 대체 부품을 선택하십시오:
LT3950IMSE#PBF
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
LT3950EMSE#TRPBF
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
LT3950IMSE#TRPBF
✅ 드롭인📋 참조 대체품 (카탈로그에 없음)
LT3950EMSE 최대 정격 & 전기적 특성
| Topology Supported | Boost, Buck, SEPIC, Buck-Boost, Flyback, Cuk |
| 입력 전압 범위 | 3 V to 60 V |
| Internal Switch Current Rating | 1.5 A |
| Internal Switch Voltage Rating | 60 V DMOS |
| 스위칭 주파수 | 2 MHz (typical, constant) |
| Current Sense Voltage | 200 mV |
| Dimming | Internal Exponential Scale PWM + External PWM Input |
| Quiescent Current (Shutdown) | < 1 uA (typical) |
| 동작 접합 온도 | 0 C to 125 C (E grade) |
| 패키지 | 16-pin MSOP-EP (Exposed Pad) |
| 실장 유형 | Surface Mount |
| MSL 레벨 | MSL 1 (per PartGenie data) |
| RoHS 상태 | ROHS3 Compliant |
| REACH Status | REACH Unaffected |
| Fault Indicator | Open-drain FAULT pin |
| 소프트 스타트 | Programmable via external capacitor |
LT3950EMSE 핀 구성
| 핀 1 | VIN — Input voltage supply (3V to 60V) |
| 핀 2 | EN/UVLO — Enable and undervoltage lockout |
| 핀 3 | CTRL — Analog dimming control input / reference |
| 핀 4 | PWM — External PWM dimming input |
| 핀 5 | SENSE — LED current sense resistor |
| 핀 6 | SS — Soft-start programming capacitor |
| 핀 7 | RT — Timing resistor (sets internal PWM frequency) |
| 핀 8 | GND — Signal ground |
| 핀 9 | PGND — Power ground (return for DMOS switch) |
| 핀 10 | SW — Switch node (DMOS drain) |
| 핀 11 | VC — Compensation node for error amplifier |
| 핀 12 | VREF — Internal reference bypass |
| 핀 13 | FAULT — Open-drain fault indicator |
| 핀 14 | FB — Feedback (LED voltage sense) |
| 핀 15 | NC — Not connected (per datasheet) |
| 핀 16 | EP — Exposed pad (thermal pad, connect to GND) |
일반적인 애플리케이션
LT3950EMSE 적합 용도: 7 애플리케이션s: Automotive LED Daytime Running Lights, Architectural and Signage Lighting, MR16 and AR111 LED Retrofit Lamps, Industrial 24V/48V Constant-Current LED Strings, Backlight Driver for Industrial Displays, Portable High-Brightness LED Flashlights, Status and Indicator LED Panels.
Automotive LED Daytime Running Lights
The LT3950EMSE is well suited to automotive DRL circuits because its 60 V internal DMOS switch withstands load-dump transients on 12 V/24 V vehicle buses, and the 2 MHz switching frequency stays above the AM broadcast band to avoid EMI interference with the vehicle's radio. Designers place a TVS clamp on the input, then configure the part in boost topology to drive a string of 6-10 high-brightness white LEDs at 1 A. The internal exponential scale dimming generator handles daytime/nighttime brightness transitions without firmware intervention, reducing MCU overhead. According to Analog Devices, the exposed pad provides a low thermal resistance to chassis-grounded PCB copper, keeping junction temperature within the 0-125 C E-spec range.
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Architectural and Signage Lighting
For architectural RGBW or tunable-white lighting, the LT3950EMSE's multitopology flexibility lets the same IC drive boost strings for high-voltage LED bars, buck arrays for low-voltage downlights, and SEPIC stages for grounded-load installations. Per the ADI datasheet, the external PWM input pin synchronizes the driver to a central DMX or DALI controller, while the internal exponential generator smooths dimming curves when no external PWM source is present. The 1.5 A switch rating supports full-power architectural fixtures up to about 30 W. LCSC and Arrow list volume pricing near $2.92 at 1ku, making it attractive for commercial-scale lighting deployments.
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MR16 and AR111 LED Retrofit Lamps
The LT3950EMSE fits inside the small form factor of MR16 and AR111 retrofit lamps thanks to its MSOP-16 EP package and 2 MHz switching frequency, which permits a sub-10 uH inductor and 1 uF ceramic output capacitor. In buck topology, the part accepts a 12 V AC-DC rectified input and regulates a constant 350-700 mA through 3-7 high-power LEDs. According to Analog Devices, the internal 60 V DMOS switch tolerates inductive ringing on the buck switching node, eliminating the need for an external snubber in most retrofits. The exposed pad must be soldered to a copper pour to dissipate the full 1.5 A at elevated ambient temperatures inside the lamp housing.
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Industrial 24V/48V Constant-Current LED Strings
The LT3950EMSE's 3 V to 60 V input range directly supports 24 V industrial bus rails and 48 V telecom supply chains, with no upstream preregulator needed. In buck-boost topology, the part regulates a constant current through an LED string regardless of whether VIN sits above or below VOUT. Per the ADI datasheet, the 200 mV current-sense voltage reduces power dissipation in the sense resistor by up to 80% versus older 1 V designs. The open-drain fault indicator pulls low during open-LED, short-LED, or thermal events, enabling integration with plant-wide alarm systems. Recommended for new industrial lighting designs.
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Backlight Driver for Industrial Displays
The LT3950EMSE drives high-current edge-lit or direct-lit backlight LED strings with high PWM dimming ratios, thanks to the internal exponential scale dimming that delivers 1000:1 dimming range without flicker. Per the Analog Devices datasheet, the constant 2 MHz switching frequency keeps ripple below the LCD panel's flicker threshold, while the programmable soft-start prevents inrush current that could damage the LED bar. Boost topology with a 1 uH/2 MHz inductor handles 18-22 V LED bars from a 12 V input. The exposed pad of the MSOP-16 package anchors to a 1 square inch copper pour for full-output operation at 1.5 A.
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Portable High-Brightness LED Flashlights
The LT3950EMSE's wide 3-60 V input range and 1 uA shutdown quiescent current suit it to battery-powered flashlight designs running from 1S to 4S Li-ion packs. Boost topology drives a single high-power white LED at 1.5 A from a 3.7 V cell, while the CTRL pin accepts a potentiometer for analog brightness control with automatic exponential scaling. According to ADI, the undervoltage lockout and programmable soft-start protect Li-ion cells from over-discharge and inrush stress. The MSOP-16 EP package plus 2 MHz magnetics fits inside a flashlight head less than 20 mm in diameter, and the exposed pad conducts heat to the flashlight body.
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Status and Indicator LED Panels
The LT3950EMSE drives multi-channel status indicator panels with constant-current regulation, eliminating the brightness mismatch that plagues simple resistor-based LED arrays. Its internal PWM dimming generator supports synchronized blinking patterns without external logic, while the FAULT pin flags open or shorted LEDs for predictive maintenance. In buck topology from a 5 V or 12 V logic rail, the part regulates 20-50 mA through each LED string. The wide input range supports both 5 V USB-powered panels and 24 V industrial cabinet indicators from a single BOM. The MSOP-16 EP footprint simplifies PCB layout versus discrete MOSFET solutions.
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추천 제품 요약
엔지니어링 참조 데이터: LT3950EMSE — 비교, 설계 지침 및 규정 준수 정보.
선택 가이드
대체품과의 비교
| 파라미터 | 이 제품 | LT3950IMSE#PBF | LT3950EMSE#TRPBF | LT3950IMSE#TRPBF |
|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | MSOP-16 EP | MSOP-16 EP - same | MSOP-16 EP - same | MSOP-16 EP - same |
| Internal Switch Current | 1.5 A | 1.5 A | 1.5 A | 1.5 A |
| Input Voltage Range | 3 V to 60 V | 3 V to 60 V | 3 V to 60 V | 3 V to 60 V |
| Switching Frequency | 2 MHz | 2 MHz | 2 MHz | 2 MHz |
| Operating Junction Temperature | 0 C to 125 C (E grade) | -40 C to 125 C (I grade) | 0 C to 125 C (E grade) | -40 C to 125 C (I grade) |
| Dimming | Internal Exponential PWM + External PWM | Internal Exponential PWM + External PWM | Internal Exponential PWM + External PWM | Internal Exponential PWM + External PWM |
| Shipping Format | Tube (PBF) | Tube (PBF) | Tape & Reel (TRPBF) | Tape & Reel (TRPBF) |
주요 차별점
- On-chip exponential scale dimming generator (vs LT3758EMSE)
- 60 V internal DMOS switch at 2 MHz (vs LM3405XMKX/NOPB)
- Multitopology flexibility in one IC (vs LP5024RSMR)
설계 노트
Estimated: at full 1.5 A switch current in a boost topology with VIN=12 V to VOUT=24 V, the LT3950EMSE dissipates roughly (1 - efficiency) x POUT. With ~85% efficiency, internal dissipation is about 3.6 W. The MSOP-16 EP package has theta_JA around 38 C/W on a 4-layer JEDEC JESD51-7 board, giving a junction temperature rise of approximately 137 C above 25 C ambient - near or above the 125 C thermal shutdown threshold. Soldering the exposed pad to at least 1 square inch of continuous inner-layer copper is critical, and forced airflow is recommended above 1 A continuous in enclosed fixtures.
Per the Analog Devices datasheet, place the input ceramic capacitor (>= 1 uF X7R) as close as possible between VIN and PGND, and route the SW node with short, wide traces to minimize EMI and voltage spikes. The exposed pad must be soldered to a continuous ground copper pour on inner and outer layers to meet the rated 1.5 A continuous current. Use at least 4 thermal vias (0.3 mm drill, 0.6 mm pad) under the EP to connect top copper to inner ground planes.
Three common pitfalls when designing with the LT3950EMSE: (1) omitting the input TVS clamp on automotive 12 V/24 V buses, which can exceed the 60 V DMOS rating during load-dump transients; (2) selecting an inductor with saturation current below 2 A, which causes sub-harmonic oscillation at peak load; (3) failing to solder the exposed pad, which raises junction temperature by 20-30 C and may trigger thermal shutdown at 1.5 A. Always verify the SS capacitor value to limit inrush current and protect the LED string on hot-plug events.
규정 준수 정보
ROHS3 Compliant and REACH Unaffected per PartGenie analysis (Oct 2026). The -PBF and -TRPBF suffixes denote lead-free Pb-free finish. AEC-Q100 automotive qualification not stated by ADI for the LT3950 family; for AEC-Q100 LED drivers, consider the LT3790EFE or contact ADI for automotive-grade LED driver options.
